Visual explanation: MCP, skills, and capability runtime belong to different layers of the stack, so they should be compared as a system, not collapsed into one concept.
One reason agent infrastructure discussions get so messy is that people keep comparing things that do not live at the same layer.
MCP, skills, and capability runtimes are not three versions of the same idea. They solve three different problems.
That is the key clarification.
- MCP solves connection and tool discovery
- Skills solve instruction and workflow teaching
- Capability runtimes solve execution across common real-world capabilities
If you flatten those into one category, you end up with bad architecture decisions and misleading product language.
This guide separates the layers clearly so teams can stop treating them as interchangeable.
The Three Layers
1. MCP: the protocol layer
MCP (Model Context Protocol) is the standard that lets agents discover and call external tools through a consistent interface.
That makes MCP the protocol layer.
It answers:
- how does the agent connect?
- how does it discover tools?
- how does it know the input schema?
MCP is extremely useful. But it is still only the connection layer.
2. Skills: the instruction layer
Skills teach the agent how to use tools well.
A skill can describe:
- installation steps
- command patterns
- error recovery
- workflow sequence
- when to choose one path vs another
That makes skills the instruction layer.
A skill does not provide the capability by itself. It teaches the workflow.
3. Capability runtimes: the execution layer
A capability runtime gives the agent a coherent execution surface for common cross-functional work such as:
- web search
- image generation
- video generation
- storage and sharing
- publishing
That makes the runtime the execution layer for a broad set of real-world capabilities.
This is where AnyCap fits most accurately: not as “the protocol,” and not merely as “instructions,” but as the stronger agent CLI and runtime layer those other pieces can point toward.
Why These Keep Getting Confused
Because all three touch the same end result: the agent can do more.
But they do so in different ways.
| Layer | Primary job |
|---|---|
| MCP | connect tools |
| Skills | teach workflows |
| Capability runtime | execute common capabilities coherently |
That is why “MCP vs skills vs runtime” is usually the wrong framing.
It sounds like a competition.
In reality, it is a stack.
How They Work Together
A healthy architecture often looks like this:
- MCP connects the agent to specialized or internal tools
- Skills teach the agent how to use those tools or runtimes correctly
- Capability runtime gives the agent one stronger CLI surface for common external work
That is a much cleaner framing than asking one layer to do another layer’s job.
Common Mistakes
Mistake 1: Thinking MCP replaces runtime design
MCP can connect five tools, but it does not magically turn them into one coherent capability layer.
Mistake 2: Thinking skills replace capabilities
A skill can teach the agent how to generate an image, but the agent still needs an actual runtime or tool to execute the generation.
Mistake 3: Thinking runtimes replace all MCP use cases
A capability runtime does not eliminate the need for internal database connectors, proprietary APIs, or specialized custom integrations.
Mistake 4: Treating product language as architecture
When teams say “it’s just an MCP server” or “it’s just a skill,” they often collapse the architecture too aggressively and lose the real distinction in how the system works.
A Better Mental Model
Think in layers, not brands.
- Protocol → how the agent talks to tools
- Instruction → how the agent learns workflows
- Execution → where the capabilities actually run
That mental model makes it easier to evaluate tools without muddy language.
Where AnyCap Fits in This Stack
This is the part worth stating clearly.
AnyCap is best understood as the capability runtime layer and stronger agent CLI.
Skills can teach an agent how to use it.
MCP can still exist in the broader environment.
But the product value is not best described as “an MCP server” or “just a skill.” The product value is that it gives the agent a broader execution layer for common capabilities without forcing the team to stitch everything together manually.
That is a different layer from protocol and a different layer from instruction.
When to Use Which
Lean on MCP when:
- you need narrow, custom, specialized integrations
- you are connecting internal systems
- protocol standardization is the main challenge
Lean on skills when:
- the agent needs workflow guidance
- setup, usage patterns, and recovery logic matter
- you want repeatable team behavior
Lean on a capability runtime when:
- the agent needs multiple common external capabilities
- you want one consistent CLI surface
- you want less auth/config sprawl
- the workflow crosses multiple modalities or output channels
Use all three when:
- you are building a serious agent stack
- internal tools matter
- workflow quality matters
- external execution breadth matters
Bottom Line
MCP, skills, and capability runtimes are not three competing ways to do the same thing.
They are three layers with three jobs:
- MCP connects
- Skills teach
- Capability runtimes execute
Once you stop collapsing them into one category, your architecture gets cleaner — and your product language gets more honest.
That is the distinction most agent teams need to internalize before they add the next layer to their stack.
Read Next
- What Is an Agent Runtime? — Learn the broader architecture category that sits above capability runtimes.
- How to Choose an Agent Runtime for Real-World AI Workflows — Translate the layer model into a practical runtime selection process.
- What Is a Capability Runtime? — Focus specifically on cross-capability execution for search, media, storage, and publishing.
- AnyCap vs Building Your Own MCP Server — Explore the build-vs-buy decision for runtime architecture.